Helpless
Bound, held, sleeping, paralyzed, or unconscious characters are helpless. Enemies can make advantageous attacks against helpless characters, or even deliver a usually lethal coup de grace.
A melee attack against a helpless character is at a +4 bonus on the attack roll (equivalent to attacking a prone target). A ranged attack gets no special bonus. A helpless defender can't use any Dexterity bonus to AC. In fact, his Dexterity score is treated as if it were 0 and his Dexterity modifier to AC were -5 (and a rogue can sneak attack him).
DEX 0 means that the character cannot move at all. He stands motionless, rigid, and helpless.
Dexterity
Any creature that can move has at least 1 point of Dexterity.
A creature with no Dexterity score can't move. If it can act, it applies its Intelligence modifier to initiative checks instead of a Dexterity modifier. The creature fails all Reflex saves and Dexterity checks.
Xarlen said:If an area effect spell goes off in a camp, and most of the PCs are asleep, what is the modifiers for a Reflex save?
Artoomis said:These quotes from the SRD need to be compared to the PHB for a truely authoritative ruling, but it looks like you automatically miss reflex saves if you are asleep.